Medical researchers from Osaka University Hospital have succeeded in repairing the weakened heart of a severe cardiac patient by applying thin sheets of muscle tissue grown from cells taken from the patient's thigh. The regenerative medicine technique -- described as the world's first in which a patient waiting for an organ transplant was successfully treated using his or her own cells -- may one day provide an alternative to heart transplant, the researchers say.

The procedure was performed on a 56-year-old male suffering from dilated cardiomyopathy, a condition in which a weakened and enlarged heart becomes unable to pump blood efficiently. The patient, who was outfitted with a ventricular assist device after being hospitalized in February 2006, had been on a transplant waiting list. Instead of receiving a transplant, the patient underwent the experimental heart treatment in May of this year.

To perform the procedure, the researchers first took about 10 grams of muscle from one of the patient's thighs. Myoblast cells (a type of muscle stem cell) were then extracted from the muscle tissue, placed in a culture solution and grown into 50-micron-thick sheets measuring about 5 centimeters (2 inches) in diameter. Several layers of myoblast sheets were then applied to the surface of the impaired heart, where they helped strengthen the muscle and restore cardiac function.

Within months, the patient's pulse rate and cardiac output (the amount of blood pumped from the heart with each contraction) returned to normal levels. The patient's ventricular assist device was removed in September, and doctors say he will be able to lead a normal life after being released from the hospital at the end of this month.

Osaka University Hospital is planning further clinical studies in cooperation with Tokyo Women's Medical University. Over the next two years, researchers will perform the "heart muscle sheet" treatment on six dilated cardiomyopathy patients under the age of 70 who have been outfitted with cardiac assist devices and are waiting for heart transplants.